Power clamping device



y 1-935- G. E. SWARTZ 2,007,483

POWER CLAMP ING DEVICE Filed March '7, 1952 44 v INVENTOR 4 52.4 6524 40? g; 52 J I I 44 w mz 45 r ATTO RN EY Patented July 9, 1935 STATES PATENT OFFICE My invention relates to clamping devices, such as jlgs,.etc. and to power 'means to operate the devices andllockingmeans to normally prevent movement of the clamp in such devices.

1- .Insuch devices itis quite desirable and, in many instances, quite necessary:thatitheclamp thereof be normally held or locked in a definite position,

either in clamping orunclamping positions and that the lock be easily released when it is desired to move the clamp. In power driven devices this feature is even moredesirous than in hand driven devices inithat an operator has more direct volitional control of thecl amp operating means than in power operated devices wherein the clamping and unclamping'is done by power other than manual power. a l 1 l I -;An objectof my invention is tOxIJIOVldG a simple, inexpensive, easily operable. and efiicient power ,drivenclamping devicehavinga power operated clamp, a self locking, self releasinglo-cking means to retain the clampin any position into which it maybe. moved, in either direction, and a simple and efficient control means for the clamp driving orjmoving-means.

-,Other' objects will be pointed out in this specification or will become obvious or vwill suggest themselves upon an inspection of this specification-and; ofthe accompanying drawing forming part of this specification. i i I attain these objects bylthe mechanism illustratively shown in the accompanying drawing mentioned above forming part of the specification, in: which, drawing:

.Figql is a section of a embodying my invention- Fig. 2 is avertical partialsection taken on line 2-2 of Fig. 1 showing relation of one of the gears to one ofthe-posts and tothe cylinder.

Fig. .3 is a vertical partial section on a larger scale taken on line 3 -3 of Fig. l showing relation of another gear to the other post.- 'Fig. 4 is a vertical partial section on a larger scaletaken on line 4-4 of. Fig. 1 showing relation .of thethird gear to the cylinder. a

Fig. 5 is a transverse section on a larger scale taken. on line 55 in Fig.2 showing the shaft-and power clamping device lockingmeans structure more clearly.

Fig. 6 is a section on a larger scale of the looking releasing mechanism of Fig. 1. The sectionis taken on the line 6--6 of Fig. 5.

Fig. 7 is a plan view of a control valve for the power means.

The drawing shows andthis specification specifically describes one type of power clamping device, but it is obvious that'the invention can be applied in different structures.

The device specifically shown and described comprises as follows:

The base A may be of any convenient form for direct reception of work or adapters and of sufficient strength for whatever load may be imposed 1 thereon.

The clamping plate B may be of any form and may have guide bushings therein or adapters thereon as conditions may impose. The ribs I!) may be provided to stiffen or strengthen the plate B especially when heavy loads are brought themon'near the middle thereof.

The posts H and I2 are secured to the plate B and depend therefrom and the lower ends thereof are respectively guided in thebase A. The rack teeth I3 and M are provided on the lower part of the respective posts.

The shaft C has the ends thereof journaled in the base.

The teeth iii are provided 'on the shaft C to mesh with the teeth l3 on the post i I. The teeth [1 are provided on the shaft to mesh with the teeth M on the post l2. The teeth I8 are provided on the sleeve at a place intermediate the teeth l6 and I! to mesh with the teeth [9 on the piston rod 20. 1

The cylinder D is secured to the base and is held against longitudinal movement thereof by the transverse key 2|. The piston 22 is in the cylinder as usual and the piston rod 23 is secured to the piston as usual and extends out through one end of the cylinder and has the above men tioned. teeth I 9 on the outer part thereof. The axis of the cylinder is so placed that 'the teeth [9 mesh with the teeth IS on the sleeve.

The "control means comprises the two way valve 24 having the exhaust port 25, the port 26 with the pipe 21, the port 28 with the pipe 29 and the intake port 30 with the feed pipe 3|. The pipe 21 leads into; one end of the cylinder and the pipe 29 leads into the'other end. The rotatable part 32 of the valve has corresponding ports. Each two of these ports at right angles to each other are connected by the passage ways 33 and 34.v i The control valve is shown for better illustration as being separate from the device but is connected thereto by the pipes 21 and 29. The con trol valve can be placed within the base if desired and the operating handle 35 thereof can project out through the wall of the base.

The sleeve I5 is journaled on the shaft.

The locking mechanism E may be supported on the inside of a wall of the base as shown.

The casing 36 of the locking mechanism has the bore 31 therein. The rotor or operating member is keyed onto the shaft C by means of the key 38 and rotates the shaft and is journaled in the bore 37. The cover 39 is a part of the sleeve and closes one end of the casing and holds the locking members therein.

The projections 40, 4|, and 42 are provided on the rotor on the respective sides'of the projections to form the grooves 42 and 43a, 44 and 44a, and 45 and 45a and the rollers 46, 47, 48, 49, 50, and 5| are disposed in the corresponding grooves between the bottoms thereof and the bore 31 in the casing and also adjacent to the corresponding side walls 52, 53, 54, 55, 56, and 51 of the projections.

The bottom of each groove forms an inclined plane in relation to the bore 31 on each side of the corresponding projection so that each groove forms a pocket which is deepest at the projection and diminishing in depth from the projection toward each end thereof.

The springs 58, 59, and Bilextend through the prongs and are provided between the corresponding pairs of rollers and normally tend to separate the same and move them into the less deep portions. of the grooves and thereby lock the shaft against self rotation in either direction.

The driving prongs GI, 62, and 63 extend from the flange or cover 39 into the corresponding grooves outwardly adjacent to the corresponding rollers and have holes therein, longitudinally thereof to loosely receive the rollers 64 to centralize the rotor in the casing.

' The device shown and described is. intended to be operated pneumatically but other fiuidic power means may be used with corresponding modifications if necessary. A hydraulic power means may be used in the deviceshown and described.

The pipes to the cylinder are shown comparatively large for quick action. In hydraulic operated devices it may be necessary to increase the size of the pipes to attain quicker action in the device.

In operation, starting from the positions of the various elements as shown in Fig. 1, air from a suitable source enters the valve through the port 30 by means of the pipe 3|, passes through the passage-way 34, then through the port 26 into the pipe 21, and then into one end of the cylinder and thereby moves the-piston inthe direction of the arrow and rotates the sleeve through the teeth mesh between the piston rod and the sleeve.

This rotation of the sleeve rotates the prongs 6|, 62, and 63 on the cover 39 to contact the rollers 46, 48, and 50 respectively and thereby moves these rollers out of their locking position and against the walls 43, 44, and 45, respectively, and thereby rotates the shaft through the keyed relation between the rotor and the shaft. Rotation of the shaft rotates the teeth I6 and I1 and moves the posts II and I2 due to the teeth mesh between them and thereby moves the clamping plate. Reversal of the shaft engagement on the posts from front to rear or reversal of the piston rod engagement from the top to the bottom of the teeth on the sleeve will result in the clamping plate moving in the opposite direction.

As soon as the power means stops operating and the shaft comes to rest in any rotative position thereof, the springs move the rollers into locking positions and thereby lock the shaft against self rotation due to pressure brought onto the clamping plate and thereby locks the clamping plate against self movement in either direction.

Normally, the pressure in the cylinder holds the clamping plate against reverse movement from any position moved into as long as the power is turned on but when the power fails or is turned off in some manner or fails in some manner, the locking mechanism prevents movement of the clamping plate in either direction.

The power means retains the clamping plate in any position, as in a work clamping position for instance, and moves the clamping plate to 1501- low up in case the work becomes loose under the clamp during operation on the work.

A reversal of the power means in the cylinder, as for unclamping of work for instance, cause reversal of the operation described above in substantially the same manner.

The round rollers shown and described may be replaced by flat faced shoes.

I am aware that clamping devices have been made prior to my invention and, therefore, I do not claim the same broadly but I am not aware that such devices have been made'prior to my invention with fluid power means to operate the clamp and with automatic locking means to retain the clamp in any position thereof when the same is not operated by the power means and to automatically release itself when the power means starts moving the clamp.

Therefore, I do not claim clamping devices broadly, but I do claim broadly the operating means and the control means and the locking and releasing means. I

Since my invention is applicable to clamping devices different than the one specifically shown and described herein and, since I am aware that changes and modifications can be made in'the parts specifically shown and described and in the arrangements thereof within the scope and intent of my invention and of the appended claim, I do not limit myself to the precise application of my invention as shown and described nor to the precise structure and arrangement of elements or parts as shown and described.

I claim: A work clamping device comprising a base, a work clamping plate movable toward and away from said base for work clamping and unclamping, a post depending from said plate and guided in said base and having a rack thereon, a. power cylinder in said base to move said plate oppositely, a piston rod extending from said cylinder, teeth on said piston rod, a shaft journaled in said base, teeth on said shaft in mesh with said teeth on the piston rod, teeth on said shaft in mesh with said rack, and a control means for the clamping and unclamping comprising a valve and an operating handle thereon to move the valve to admit fluid pressure to one end of said cylinder and at the same time exhaust fromthe other end thereof.

- GUY E. SWARTZ. 

